Electronic beam deflection circuits



- ELECTRON GUN E. BRUECHE ETAL ELECTRONIC BEAM DEFLECTION CIRCUIT Filed May 26, 1939 INVENTORS ERNS T BR UECHE 4 50 NAGE'L ATTORNEY Patented Mar. 17, 1942 ELECTRGNIJ BEAM DEFLECTION CIRCUITS York Application May 26, 1939, Serial No. 275,822 In Germany January 22, 1938 (Cl. 25ll-36) 3 Claims.

The invention relates to a circuit arrangement for a pair of deflection plates operated with an alternating potential and serving for deflecting an electron ray such as used for instance in Braun tubes or in an arrangement for establishing an intermittent electron ray, a so-called phase diaphragm. As is known, with such deflection there takes place in general an energy exchange between the pair of deflection plates and the electron ray whereby either energy is consumed for deflecting the ray or energy is withdraw from the ray in an uncontrollable manner.

By a phase diaphragm is meant a means for controlling the position of a cathode ray beam by means of an alternating potential and means co-operating therewith for allowing the cathode ray beam to pass through the latter means only at certain phases of the potential impressed on the means for controlling the position of the cathode ray beam.

An electrostatic pair of deflection plates in a circuit according to the invention is suited for use in a phase diaphragm for an electron optical phase lens such as has already been suggested. This will be explained in greater detail in the description of the drawing in which The figure shows a proposed arrangement of an oscillator employing a phase diaphragm.

The figure shows an example of construction of a circuit arrangement of a phase diaphragm and phase lens in accordance with the invention.

The phase diaphragm consisting of the plate pair I and perforated diaphragm 2 acts such that it permits an electron current to pass through only when the alternating potential of said phase diaphragm passes through the one of its apex values. Therefore, the electron current will be interrupted in synchronism with the deflection potential. This intermittent electron current now impinges a travel time device 5, such as for instance a pendulum multiplier serving for the production of electrical oscillations. Cathodes 6 and I are capable of emitting secondary electrons and there is provided an anode 8 of the multiplier. The oscillations appear in the oscillatory circuit comprising the capacity 9 and the inductance In, said circuit being connected to 6 and l. A part of these oscillations is derived from tuned circuit 9 and Ill by transformer H and applied to the oscillatory circuit connected across the plate pair I and comprising the inductance l2 and the variable condenser 13 whereby a suitable coupling such as for instance an inductive coupling is provided to cover the energy losses caused by the damping. If the applied oscillations appear in the rhythm in which the electron ray is interrupted in the diaphragm, the coupling between travel-time device and phase diaphragm produces an automatic stabilization of the interruption by the once interrupted electron current.

What is claimed:

1. In a cathode ray tube apparatus, means for developing a cathode ray beam, means for deflecting said beam comprising a pair of electrostatic deflecting plates, an apertured member positioned immediately adjacent said deflecting plates whereby the cathode ray beam can pass through the aperture in said member only during definite and limited phases of energizing potential to be applied to said deflecting plates, target means comprising electron multiplier means having opposed plate members, a tuned circuit connected between the opposing plate members of said multiplier and means for feeding back a portion of the energy in said tuned circuit and impressing said fed back energy onto said deflecting means as energizing potential.

2. Apparatus in accordance with claim 1, wherein one of the opposed plate members in the electron multiplier is apertured to admit the passage therethrough of said electron beam.

3. Apparatus in accordance with claim 1, wherein there is provided in addition a tunable circuit connected to the pair of electrostatic deflecting plates.

ERNST BRUECHE. ALFRED RECKNAGEL. 

